Semiconductor device manufacturing processes include cleaning semiconductor wafers (hereinafter, briefly referred to as wafers) by processing liquid, such as a chemical solution or a rinsing solution. A cleaning processing includes supplying a chemical solution, such as DHF solution (diluted HF) to a wafer to process the wafer with the chemical solution, supplying a rinsing solution, such as deionized water to the wafer to process the wafer with the rising solution, and drying the wafer.
Conventionally, a wafer drying method includes, for example, a vapor drying method in which a wafer is dried with vapor of organic solvents, such as IPA (isopropyl alcohol), while rotating the wafer. Also, a dehumidified air (low humidity air) may be supplied to a wafer in order to suppress generation of watermarks, thereby reducing the humidity around the wafer. One example of supplying a dehumidified air is disclosed in Japanese Utility Model Laid-Open Publication No. P6-9130. However, because a dehumidified air always has to be supplied to the surroundings of the wafer during the drying processing, a wafer processing cost is increased.
Japanese Patent Laid-Open Publication No. 2007-263485 discloses supplying a low humidity air, such as IPA, as a drying solvent, only when it is required. According to this method, a time for supplying a low humidity air can be reduced, and thus a wafer processing cost is reduced, in comparison with the method disclosed in Japanese Utility Model Laid-Open Publication No. P6-9130.
However, even in the method disclosed in the Japanese Patent Laid-Open Publication No. 2007-263485, a low humidity air must fill out a chamber when the air is supplied. Therefore, a considerable amount of low humidity air is still required. Accordingly, a need to reduce an amount of low humidity air is still required.
Japanese Patent Laid-Open Publication No. 2004-349470 discloses supplying a dry air (low humidity air) to a chamber in which a substrate is received, the substrate having been processed with a cleaning solution. Thus, the evaporation of the cleaning solution can be accelerated and the generation of watermark can be suppressed. However, this method still requires filing a chamber with a low humidity air. Therefore, a considerable amount of low humidity air is still required, and the reduction of an amount of the low humidity air is required.